Electronic devices are increasingly being developed that are able to bend, flex and twist, such as in wearable electronics. These mechanical requirements present reliability challenges on mechanical components, circuit boards and interconnects, as well as electronic components. In order to limit the stress and strain to these components while still maintaining flexibility, mechanical provisions must be put in place.
Flexible printed circuit boards provide circuit board structures that are less rigid than earlier generation printed circuit boards, and enable varying degrees of flexing, bending and twisting. Flexible interconnects between conductive wires and flexible printed circuit boards are needed for applications where durability and flexibility are a concern.
In conventional structures, an interconnection is made between the conductive wire and the flexible printed circuit board by first forming a contact pad on a top, outer surface of the flexible printed circuit board and then attaching an end of the conductive wire to the contact pad, typically using solder or conductive adhesive. This forms a rigid interconnect between the contact pad and the conductive wire. However, rigid interconnections are susceptible to breaking when subject to physical stress, especially in those applications more prone to bending, flexing and twisting of the flexible printed circuit board.